Screw-propeller



B. P. SPARROW.

SCREW PROPELLBR.

Patented Deo. 11, 1888.

UNITED STATES PATENT OFFICE.

BENJAMIN F. SPARRO\V, 0F BOSTON, MASSACHUSETTS.

' SCREW-PROPELLER.

SPECIFICATION forming part of Letters Patent No. 394,414, dated December11, 1888.

Application filed December l, 1887. Serial No. 256,711. (No model.)

fo all whom, it may concern.'

Be it known that I, BENJAMiN F. SPARROW, a citizen of the United States,and a resident of Boston, in the county of Suffolk and State ofMassachusetts, have invented a new and useful Improvementiu Propellersfor Navigable Vessels, of which the following, taken in connection withthc accompanying drawings, is a specification.

The object of my invention, which I designate the centripetal propeller,is to produce' a rotating series of blades or tlukes attached byindependently curved or sinuous arms to the propeller-shaft in such amanner as to offer the least impediment in their passage through thewater, as also to assure an open central space adjacent to the outer endof said shaft to avoid the reaction of the current and consequentproduction of what is technically known as dead-water. I attain theseresults through the novel construction of the sustaining-arms and theangle at which said blades are thereto attached to exert in their rotarymotion when submerged a maximum pressure against the water when forgingahead with the least disturbance or churning thereof, as also to obtaina like result in reversing the propeller to retard or stop the vessel.The celerity and power I secure through the combination ot' thesefeatures become the most essential factors in the avoidance of oceancollisions.

In practical demonstration of the efficiency of my invention I attaingreater speed with a medium expenditure of power with a less disturbanceof water. I also avoid the strain ordinarily occasioned bythe propelleras at present constructed.

A more specific description of my invention, its operation andconstruction will be observed from reference to the drawings, forming apart of this specification, in which- Figure 1 illustrates in elevationthe general application of my invention as applied to a steam-vessel,Fig. 2 being an end elevation of the propeller, exhibiting the sinuousarms springing from the shaft. Fig. 3 is a transverse section of one ofsaid arms. Fig. 4 indicates in said elevation the nukes placed obliquelyto the propeller-shaft; and Fig. 5, a

similar view illustrating one or more tlukes attached to a bifurcatedshaft, wherein the arms (upon one of which the linkes are broken olf)lie parallel.

Similar letters of reference indicate like parts in the several viewsthereof, referring to which- A designates the propeller stub-shaft,having connected thereto by suitable devices (not herein shown) thesinuous arms B B, diverging in a manner and for the purpose of formingan open space adjacent to the end of the propeller, as at C. 'lhisobviates any reactionary current and permits the liukes D to cut densewater in their rotation without causing the ebullition ordinarilyattendant upon screw propellers. Said tlukes I) are set at such angle orpitch as will obtain the greatest power with the least disturbance ofthe medium surrounding them, preferably at an approximating angle ofsixty-eight degrees to the plane of their axis, this position assuringthe best obtainable results in speed combined with unappreciable jar.Said flukes may be of multiform shape, as I do not confine myself to anyparticular design so long as I maintain an open center or space near theadjacent ends of the flukes and so adjust said fiukes that the water maybe cleanly cut at every revolution of the same and freely expelledtherefrom.

In Fig. 5 I exhibit the supporting-arms h2 elongated to support two ormore iiukes placed at divergent angles, as at E E. Said shaft isbifurcated from the shoulder A, permit-ting the arms to be parallel,that the open center may still be preserved, while to insure strengthand facilitate the passage of said arms through the water they aredouble convex in form, as indicated in Fig. 3, the apexes F F separatingthe element without commotion in the same manner as the tlukes.

Having described my invention and its operation, what l desire to secureby Letters Patent of the United States isl. An improved propeller fornavigable vessels, substantially as herein described, having two or moreflukes, I), radially extending from bifurcated or sinuousdouble-convened supports B B2, arranged and constructed to operate incombination with the hub or boss IOO of the propeller A n a manner topermit an adapted to secure Centrally a rapid and unopenng adjacent tosaid propeller-shaft and obstructed expulsion of water from said pro- 1oto ej eet the Water therefrom. peller-shaft. 2. In an improved propellerfor navigable 1 ,v

5 vessels, substantially as speeied, the stub- BENJAMIN 11' SPARROW'shaft A, terminating in bifureated or snuous Vtnesses:

arms B B2, combined to eoaot with the par- WM. H. MILLER, allel orradially-Constructed flukes D E E, H. E. REMICK.

